Heat exchanger

Abstract

A heat exchanger in which the main component is formed of a plurality of elongated strips of rigid heat conductive material. The strips are generally transversely aligned and wound into a coil formation in which each of the surfaces of each strip is disposed in facing relation to the opposite surface of an adjacent strip in the coil. Each pair of facing surfaces is ridged to provide passage defining portions and force transmitting portions with certain of the strips having both end edges thereof sealingly secured to the corresponding end edges of an adjacent strip so as to define a longitudinal fluid passage having a coil formation other of the strips have both end edges thereof disposed out of sealing engagement with corresponding end edges of the adjacent strip so as to define a transverse fluid passage. The force transmitting portions of each pair of facing surfaces are disposed in force transmitting relation with respect to one another so that forces created by the fluid pressure and temperature conditions within the fluid passages tending to deform the strips are resisted to thereby prevent deformation which would otherwise occur in the absence of the force transmitting relationship and permit the utilization of wall thicknesses less than that required to be self-sustaining in order to prevent such deformation. By providing a cyclical fluid infeed, a peristaltic action through the coil formation fluid passage is achieved.

What is claimed is: 
     
       1. A fluid heat exchanger comprising a plurality of elongated strips of rigid heat conductive material,   each of said strips having a cross-sectional configuration which is elongated in a direction transverse to the elongated extent of the strip so as to provide a pair of spaced relatively thin end edges and a pair of relatively wide opposed surfaces extending between said end edges,   said strips being generally transversely aligned and wound into a coil formation in which each of the surfaces of each strip is disposed in facing relation to the opposite surface of an adjacent strip in the coil,   each pair of facing surfaces including passage defining portions and force transmitting portions,   certain of the strips having both end edges thereof sealingly secured to the corresponding end edges of an adjacent strip so as to define with the passage defining portions of the facing surfaces associated therewith longitudinal fluid passage means having a coil formation flow direction extending generally in the direction of longitudinal extent of said strips,   certain of said strips having both end edges thereof disposed out of sealing engagement with corresponding end edges of the adjacent strip so as to define with the passage defining portions of the facing surfaces associated therewith transverse fluid passage means having a flow direction extending generally in a direction transverse to the direction of longitudinal extent of the strips,   the force transmitting portions of each pair of facing surfaces being disposed in force transmitting relation with respect to one another in the direction said facing surfaces face one another so that forces created by the fluid pressure and temperature conditions within said fluid passage means tending to deform said strips in said facing directions are resisted to thereby prevent deformation which would otherwise occur in the absence of said force transmitting relationship and permit the utilization of wall thicknesses less than that required to be self-sustaining in order to prevent such deformation,   means for supporting said coil formation including the end loops thereof,   means for directing heated fluid into and out of said transverse fluid passage means, and   means for cyclically introducing successive incremental fluid portions to an inlet end of said longitudinal fluid passage means so that such incremental fluid portions will flow to an outlet end thereof in said coil formation direction with a peristaltic action by virtue of the pressure field developed therein as a result of heat addition thereto through heat exchange with the heated fluid in said transverse fluid passage means.   
     
     
       2. A heat exchanger as defined in claim 1 wherein said incremental fluid portion introducing means is connected to the radially inner end of said coil formation as the inlet end thereof. 
     
     
       3. A heat exchanger as defined in claim 1 or 2 wherein said coil formation supporting means includes a cylindrical housing, one end of which is disposed in supporting relation to the exterior end loop of said coil formation. 
     
     
       4. A heat exchanger as defined in claim 3 wherein said cylindrical housing has a second parallel coil formation peripherally supported within the opposite end thereof. 
     
     
       5. A heat exchanger as defined in claim 4 wherein said heated fluid directing means includes a burner assembly extending into said cylindrical housing. 
     
     
       6. A heat exchanger as defined in claim 1 wherein the sealing securement between one pair of corresponding end edges is effected by a folded portion formed integrally with said one pair of corresponding end edges. 
     
     
       7. A heat exchanger as defined in claim 1 wherein said coil formation is a spiral and the facing directions of said surfaces are radially inwardly and radially outwardly with respect to the axis of the spiral coil formation. 
     
     
       8. A heat exchanger as defined in claim 1 wherein said strips are formed of metal. 
     
     
       9. A heat exchanger as defined in claim 1 wherein the pair of facing surfaces associated with said transverse fluid passage means includes indentations and projections, said force transmitting portions being provided by said projections and being in metal-to-metal contact. 
     
     
       10. A heat exchanger as defined in claim 9 wherein said indentations and projections are knurled in each surface in generally parallel relation extending transversely from one end edge to the other end edge thereof. 
     
     
       11. A heat exchanger as defined in claim 10 wherein the knurled indentations and projections in one of the pair of facing surfaces extend transversely in a direction at an angle with respect to the knurled indentations and projections in the other of said pair of facing surfaces.